Two-piece capsule trigger unit for initiating pyrotechnic elements

ABSTRACT

The invention relates to trigger units for initiating pyrotechnic elements which usually consist of a switch and control unit, ignition means and an ignition charge body. Said switch and control element is triggered by way of an electric coupling via a line in order to initiate ignition. The line for the electric coupling and the dimensions of the switch and control element which are usually accommodated in an IC housing complicate the design and the automatic assembly of the trigger units. According to the invention, the switch and control element ( 1 ) is surrounded by a first shell ( 2 ). Said first shell ( 2 ) is connected to a second shell ( 1 ) which contains the ignition charge body ( 23 ). The invention is further characterized in that the ignition means ( 19 ) dip into said second shell ( 21 ).

BACKGROUND OF THE INVENTION

The invention relates to a trigger unit for initiating pyrotechnicelements.

By pyrotechnic elements are to be understood all elements which, as aresult of the application of a electric voltage, preferably incorrection with coded signals, trigger a pyrotechnic effect that has adesired result, for example the ignition of an explosive charge or thetriggering of the gas generator of an air bag or belt tightener. Thus,inter alia fuses, in particular detonating fuses for civil andhigh-security domains (automotive, military and oil-field domains),ignition elements and gas generators belong to the pyrotechnic elements.

Electronic fuses whose ignition lines have commercially available plugs,for example DIN plugs, jack plugs, RCA plugs or BNC plugs, with whichthe electrical connection to the terminal lines of other fuses and thedetonating machine is established, are known from EP 0 849 562 A2. Theseknown electronic fuses each have an ignition line of a specific lengthwhich end initially in, for example, a jack plug. Emerging from thisplug there is a further line (bus line) which ends in a plug socket thatis compatible with the jack plug. The plug and plug socket of a fuse arewired in such a way that the individual poles are short-circuited whenthe former are plugged together. The fuses are delivered with plugsplugged into the socket. This is to provide protection againstunintentional ignition, in particular in the case of an external voltageeffect and high-frequency loading Before the fuse is assembled, theignition line with the plugs connected thereto must be soldered onto theelectronic circuit of the fuse.

Electric fuses in which the wires of the ignition line are embedded, ina twisted state, in the stopper sealing the housing of the fuse areknown from DE-OS 28 24 568. A specific length of the ignition line isassigned to the fuse. If required, the components of a plug connectioncan be connected to this ignition line. Fuses equipped in such a wayhave the disadvantage that the ignition line attached thereto takes upmore space and is heavier than the fuse itself.

Moreover, an ignition line that is already connected to the ignitionmeans, for example an ignition cap, or to the hybrid containing theelectronic components complicates the assembly of the fuses Beforeassembly of the known fuses, the ignition line must be soldered orwelded onto the hybrid or the ignition cap. The ignition line that iscoiled and which is substantially large in terms of volume and mass,hangs from these small dimensioned parts, on the flexurally slack wires,whereby manual assembly of the components of the fuses is complicatedand mechanical assembly becomes expensive and has long cycle times.

SUMMARY OF THE INVENTION

It is therefore the object of the present invention to purpose a triggerunit for initiating pyrotechnic elements that can be produced in arational manner.

The object is achieved by surrounding the switch and the control unit bya first housing case, the first housing case being connected to a secondhousing case which contains the charge body, and by having the ignitionmeans go right into the second housing case.

Advantageous developments of the invention are claimed in the subclaims.

The trigger it in accordance with the invention for initiatingpyrotechnic elements is composed of two housing cases. The first housingcase surrounds a stitch and control unit, for example in the case of anunfinished or base fuse the so-called hybrid. The hybrid comprises interalia the electronic circuit arrangements for addressing a fuse and, ifapplicable, for fixing the ignition point. Connected to this firsthousing case there is a second housing case which contain the chargebody. This is, for example, in the case of a detonating fuse, thedetonating capsule that is charged with the initiating detonating agentor, in the case of a belt tightener, the propellent charge for thegeneration of gas. Going right into this second housing case is theignition means that is connected to the switch and control unit andwhich is not surrounded by the first housing case. The switch andcontrol unit can consist of a printed circuit board on which sensitiveelectronic components are arranged. Owing to the fact that the switchand control unit is surrounded, in accordance with the invention, by astable housing case, it can even be handled by automatic handling andloading machines for the mechanical assembly of a trigger unit withoutthe electronic components being endangered. Moreover, storage andfurther processing are simple and inexpensive on account of the compactform.

Since the switch and control unit is surrounded by its own housing case,in view of the diameter of this housing case it is not necessary to payany heed to the diameter of the housing case for the charge body. Thisis advantageous, for example, if the switch and control unit isaccommodated in an IC package or, for example, bulky capacitors are usedwhose dimensions exceed the diameter of the housing case of the chargebody. In this case, the diameter of the housing case for the switch andcontrol unit can be greater than the diameter of the housing case forthe charge body.

Owing to the fact that the charge body and the switch and control unitare arranged separately from each other in their own respective housingcases, it is possible, moreover, to surround the switch and control unitwith a housing case that has a substantially greater wall thickness thanthe housing case of the charge body, for example the detonating capsuleof a fuse. As a result of this equipping, the sensitive electroniccomponents of the switch and control unit are not only protected againstdamage during handling, in the case of mechanical assembly, but alsoagainst the influences to which the trigger units are subject duringtheir use. For example in the case of detonating fuses, in particularif, in the case of blasting at time intervals by detonating fuses, greatdynamic pressure, shock and/or impact loads are exerted on the not yetignited fuses, the so-called hybrid, the switch and control unit forfuse-addressing and for fixing the ignition point, is protected fromthese effects of pressure and impact on account of the greater wallthickness of the housing case before there is premature failure. Thewall thickness and, in particular, the material of the housing case canbe matched to the respective case of loading. So that an electronic fuseis optimumly protected against the effects of preceding fuse explosions,in particular with blasting at intervals, it is possible to avoid damageto the hybrid on account of pressure and shock effects in the beatpossible way by means of the choice of the materials, for example steel,brass or copper. In order to be able to withstand the effects of thepressure in an optimum manner, in particular when there is blasting atintervals, the first housing case should withstand a dynamic pressureload of at least 100 MPa without deformation. Separate protectionmeasures as used in the case of known fuses, for example the fitting ofreinforcing or protecting tubes over the sensitive portion of theelectronics unit, are superfluous.

In a further advantageous development of the invention, the switch andcontrol unit is to be embedded in the first housing case in a hardened,non-metallic material. This can be effected in a preceding separate stepof manufacture or, if the switch and control unit has been inserted intothe first housing case, it is possible, for example, for plasticsmaterial, preferably polyvinyl chloride (PVC), polyurethane (PU) or elsepolyamides (PA), to be injection-moulded around it. Encapsulation,preferably with epoxy resins, is likewise possible. As a result of theinjection-moulding or encapsulation, the switch and control unit is notjust fixed in its position. The first housing case, as a result of beingcompletely filled with the corresponding material, attains additionalelastic rigidity against external pressure and shock effects.

The terminal contacts of the Switch and control unit are brought out ofthe first housing case at its two ends so that the electrical couplingfor ignition is possible by way of a terminal to the ignition line, forexample by means of a plug and plug socket, and to the ignition means,for example an ignition cap.

In a further advantageous development of the invention, the materialthat surrounds the switch and control unit can project from the firsthousing case in the form of a stopper at least on the side that facesthe charge body, for example, a detonating capsule. This stopper is tobe formed in such a way that it cam be inserted into the second housingcase as a sealing and fastening element. In the case of mechanicalassembly of the trigger unit, for example an electronic fuse, the firsthousing case with the stopper can be inserted into the second housingcase with the charge body, for example a detonating capsule that ischarged with initiating explosive. Then a connection can be establishedbetween the first and the second housing case, for example by adheringthe stopper to the second housing case or by means of a form-lockingconnection by mechanical deformation of the second housing case, forexample by swagging, camming action or crimping. The stopper, which,whilst projecting out of the first housing case, extends into the secondhousing case, assists the connection of the two housing cases andprovides the connecting point with appropriate mechanical rigidity.Furthermore, it can be used to seal the second housing case, inparticular, in a moisture-proof manner.

The first and the second housing case can be connected together in aform-locking, force-locking or substance-locking manner, in which casethe mature of the connection depends upon the materials of the twohousing cases, the loading that is to be expected during their use andalso the handling when the two housing cases are brought together duringassembly.

Instead of soldering the line for electrical coupling, for example anignition line, directly onto the terminals of the switch and controlunit that project out of the first housing case, the first housing casecan also carry at its free end the coupling portion of a plug connectionbetween the trigger unit and the line for the electrical coupling, theignition line. As a result, the trigger unit no longer supports any linethat is fixedly connected to it. A base fuse, for example, is, as aresult, very compact in terms of its dimensions and can be equippedmechanically in a particularly advantageous manner, can be connected tothe second housing case, to the detonating capsule, and subsequently canbe packed.

Those materials, in particular, with which injection-moulding or castingaround the switch and control unit in the first housing case is effectedare suitable as the material for the coupling portion. The material,with which the first housing case is filled, can then assume the form ofa plug socket or a plug at the free end of the housing case. Whensecuring the coupling portion to the trigger unit, seceding of thatcoupling portion with which the line for electrical coupling, theignition line, must be equipped, automatically follows.

Instead of moulding a coupling portion of a plug connection from thematerial in which the switch and control unit is embedded, it is alsopossible in the case of a fuse the detonating capsule to form the firsthousing case as a coupling portion at its end that is remote from thecharge body. Thus, for example, the housing case can project beyond thecylindrical body with the switch and control unit that fills the housingcase and can form a plug socket. In order to fix the plug of the line,it is possible to provide openings in the housing case wall into whichspurs an the plug engage. In addition, other known elements that securethe plug connection can be provided. The advantage of this plugconnection is the high level of stability and the protection againstbending and in particular against kinking during the use of the triggerunit, in particular the fuse.

In a further development of the invention the coupling portions of theplug connection are each equipped with an orientation aid so thatconnection of the coupling portions is possible in just one orientation.As a result, when connecting the line to the electrical coupling, wrongconnection are to be prevented from being established that could lead tothe disturbance, failure or even to the unintentional self-ignition ofthe trigger unit. The orientation aids can be plug chicanes, forexample. These are inter alia irregular cross sections of the plug andplug socket so that insertion is only possible in one orientation. Inaddition, the arrangement of the terminals can be used to form anorientation. If the plug and plug socket have a symmetrical crosssection, the terminal pins or contact sleeves can, for example, bearranged in one diagonal in such a way that they are distributed acrossthe respective cross section of the coupling portion or in such apattern that even here it is only possible to couple the two couplingportions, plug and plug socket, in one orientation.

Further advantages emerge if the coupling portions of the trigger unitand the line for the electrical coupling are equipped with interlockinglocking elements that establish a connection that is secured againstbeing broken unintentionally. The locking elements, for example claws ofso-called stop lamellae that engage into a groove, or a web ring thatlatches into the groove, a cap nut on the plug which is screwed togetherwith the plug socket, or a bayonet catch, secure the two couplingportions, plug socket and plug, against being drawn apartunintentionally and thus undoing the connection. The plug connections ofthe fuses that are provided for rugged conditions in mines, quarries andin explorations, for example, are to be able to tolerate high tensileforces, as far as possible above 100 N, without the plug connectioncoming undone or the plug connection becoming loose.

In a further advantageous development of the invention, the couplingportions of the plug connection are equipped with sealing elements.Thus, for example, the contacts of the plug can be surrounded with asealing ferrule which is accommodated and enclosed by the plug socket.The sealing ferrule is additionally covered by stop lamellae, the clawsof which latch into a groove is of the plug socket. As a result of theplug connection that has been described, the contacts are protectedagainst atmospheric influences, in particular against moisture, thisbeing necessary, for example, for the use of detonating fuses inquarries, in mining and in explorations. The plug and plug socket can,for example, also be protected against the penetration of moisture byway of interconnected sealing rings.

In a further development of the invention, the number of contacts of theplug or the plug socket as well as their arrangement is matched to theuse of the trigger unit. As a rule, two contacts suffice, although, forexample in the case of detonating fuses, it can be necessary to providemore than two contacts, in a maser conditional on a special sequence ofdetonations or the arrangement of the fuses. Furthermore, thearrangement of the contacts can contribute to raking impossible a wrongconnection of a plug or a plug socket.

The electronic control of the trigger unit, for example the setting ofthe ignition point of detonating fuses in the case of explosions at timeintervals, is effected by means of semiconductor integrated circuits,with their modules being accommodated in an IC package in a furtherdevelopment of the invention. On account of the compact construction andthe secure accommodation in the package it is possible to test theterminals of the IC by means of testing processes with a fuse function.IC-packages can easily be processed on prefabricated printed circuitboards on account of the terminals that are directed out in a definedmanner. The use of encapsulated, prefabricated integrated circuitsprovides the advantage that these circuits are already tested at thesite of their manufacture in all the temperature ranges in which use ispossible so that no trigger needs to be singled out on account of adefective switch and control unit only after a trigger unit has beenassembled. Whether for detonating fuses, belt tighteners or gasgenerators for air bags, the electronics unit may not have any defects.It is therefore more cost-effective to reject just the defectiveelectronics unit (IC package) than it is to reject a complete triggerunit Moreover, the circuits that are accommodated in an IC packagepresent special advantages in the case of automatic handling during thefitting of the printed circuit boards in chip on board technology onaccount of the high assembly) demands on the product.

In a further advantageous development of the invention at least thefirst housing case of the trigger unit has an identifying marking. Theidentifying marking can, for example, consist of a legible inscriptionor even of a bar code. It can contain the data that is relevant to theuse of the trigger unit, for example the manufacturer, the typedesignation, the legal identification marking and, in the case of fuses,in addition, the time stage or the ID number.

The identifying marking does not need to be limited to the first housingcase. It can also be applied to the second housing case. With separatemanufacture of a switch and control unit, a base fuse, for example, andthe charge body, for example a detonating capsule, when later broughttogether to form a trigger unit, an electronic fuse can result onaccount of the identifying marking on the two housing casesnon-interchangeable association of the portions which can be assembledtogether.

The invention is explained in greater detail with reference todetonating fuses as an exemplifying embodiment. On account of thedifferent structural forms of other trigger units, for example belttighteners or gas generators of air bags, the embodiments can differfrom one another.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 shows, in section, the hybrid of a detonating fuse beforeinstallation in the first housing case;

FIG. 2 shows, in section, the finished assembled base fuse of adetonating fuse before assembly with the detonating capsule;

FIG. 3 shows, partly in section, the finished electronic detonating fusewith ignition line connected thereto;

FIG. 4a shows, in section, the coupling portion of the ignition line,the plug, in the plane of the contacts;

FIG. 4b shows the coupling portion according to FIG. 4a in cross sectionat the point specified;

FIG. 4c shows the coupling portion according to FIGS. 4a and 4 b in aview that is turned through 90°;

FIG. 5 shows, partly in section, an electronic fuse with an ignitionline, connected by way of a plug connection, and codings on the basefuse and detonating capsule;

FIG. 6a shows, in a longitudinal section through the locking elements, aplug connection in which the fat housing case is formed as a plugsocket;

FIG. 6b shows the same plug connection in a longitudinal section throughthe orientation aids;

FIG. 6c shows a cross section through the plug connection at the pointspecified in FIG. 6b; and

FIG. 7 shows a longitudinal section through a cinch plug as a plugconnection.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The hybrid 1, the switch and control unit, of an electronic fuse that isready for installation in a first housing case 2 is shown in FIG. 1 thehybrid 1 comprises inter alia the electronic components which arerequired for addressing the fuse and, if applicable, for fixing theignition point. These electronic components are enclosed by an ICpackage 3 which is soldered onto a printed circuit board 4. Theterminals 5 of the ignition means, in the present exemplifyingembodiment an ignition cap, and also the terminals 6 of the contact pins7 of a plug socket 8 are fitted onto this printed circuit board 4. Theignition line is connected to a plug by way of this plug socket 8.

The hybrid 1 and also the terminals are embedded in a hardened,non-metallic material 9. The material can, for example, be a plasticsmaterial or casting resin. A cylindrical body 10 is formed thatsurrounds the hybrid 1 and also the terminals. In the assembled stateaccording to FIG. 2, the housing case 2 extends as far as the collar 11.The plug socket 8 is formed from the portion that projects out of thefirst housing case 2. It extends as far as the collar 11 which seals thehousing case 2. A stopper 12 projects out of the housing case 2. Thisstopper 12 is used as a sealing and fastening element in the secondhousing case.

An orientation aid 13 is visible on the inner wall of the plug socket 8.It is a thickened portion with a triangular cross section that extendsin the longitudinal direction of the contact pins 7 and which mustengage into a correspondingly formed groove in the plug (FIGS. 4b and 4c). As a result, a plug-connection between the plug and plug socket ispossible in only one orientation.

The first housing case 2 has a wall thickness that is greater than thatof the second housing case, As a result, it is possible to protect thehybrid in particular from dynamic pressure loads, for example when usedin the secondary ignition range. Moreover, the housing case is producedfrom a material which is resistant to load such as, for example, steelor brass. The first housing case 2 has a conical taper 14 at the end atwhich it is connected to the second housing case. It thereby forms atransition to the smaller diameter of the second housing case. Moreover,this conical taper 14 serves as a stop for the conical taper 15 of thecylindrical body 10 if, for example, in the case of mechanical assemblyof the two components the housing case 2 is pushed over the cylindricalbody 10 with the hybrid 1, as indicated by the arrow 16.

FIG. 2 shows the ready-assembled base fuse 17. The first housing case 2has been pushed over the cylindrical body 10 with the hybrid 1. Thecylindrical body 10 is fixed in the first housing case 2 in the presentexemplifying embodiment by means of so-called crimping. In thisconnection, the material of the first housing case 2, is pressedconcentrically at one or more adjacent points into the material 9 of thecylindrical body 10, as effected at the concentric annular constrictionsbelow the collar 11 and above the conical taper 14 of the first housingcase 2.

The plug socket a and the stopper 12 project the first housing case 2.The ignition cap 19 is soldered onto the terminal lines 5. It isencapsulated in a shrinkdown tube 20 which serves as protection in thecame of electrostatic coupling.

The second housing case 21, the detonating capsule, is shown below thebase fuse 17. In the region of its closed end 22 it contains the charge23, the initiating detonating agent, and arranged above this the primarycharge 24. It is slipped with its open end 25 in the direction of arrow26 over the ignition cap 19 and onto the stopper 12. The ignition cap 19thereby goes right into the empty region 27 of the second housing case21.

The diameter d of the second housing case 21, as can be seen from therepresentation in FIG. 2, is smaller than the diameter D of the firsthousing case 2, because its diameter d does not need to be matched tothe IC package of the hybrid. The wall thickness of the second housingcase 21 is substantially less than the wall thickness of the firsthousing case 2, because it does not need to protect a sensitiveelectronics unit. The second housing case can be produced separatelyfrom the base fuse 17. This simplifies the production of an electronicfuse. The production of the base fuse is not only simplified in theabsence of the explosive of the detonating capsule, but also becomessafer.

FIG. 3 shows a complete electronic fuse 28. The second housing case 21has been slipped over the stopper 12 of the base fuse 17 and in thepresent exemplifying embodiment has been connected to the base fuse 17by inward crimping, evident from the two concentric constrictions 29.The stopper 12 of the base fuse 17 thereby establishes the connectionbetween the first housing case 2 and the second housing case 21.

FIGS. 4a to 4 c show the plug 30 that is compatible with the plug socket8, in two longitudinal sections that are perpendicular to each other,and also in one cross, section, with which plug connection of theignition line 31 is made to the electronic fuse.

FIG. 4a shows a longitudinal section through the plug 30, with thesection extending in the plane of the two terminal wires of the ignitionline 31. The two wings end in two contact sleeves 32 for receiving thecontact pins 7 of the plug socket S. The two contact sleeves 32 areembedded in a so-called sealing ferrule 33 which can be inserted intothe plug socket 8.

A view of the section through the plug 30 in the region of the sealingferrule 33 according to FIG. 4b Shows that a so-called stop lamella 34is arranged above and below the sealing ferrule 33 with the contactsleeves 32, in addition, in each case. These stop lamellae 34 areelastic and they latch into the grooves 37 of the plug socket 8 (FIG. 5)by means of their claws 35 that are arranged at the ends when thesealing ferrule 33 has been inserted far enough into the plug socket 8.

A so-called orientation aid 36 can be seen on the sealing ferrule 33 inFIGS. 4b and 4 c. It is a groove that is arranged on one side in thesealing ferrule 33 of the plug 30 and which renders possible insertioninto the plug socket 8 in just one orientation, because the orientationaid 13 that is known from FIG. 1, an appropriately shaped thickenedportion in the wall of the plug socket 8, must engage into this groove36. A reliable connection between the ignition line 31 and the fuse 28is only guaranteed after the plug 30 has been completely inserted intothe plug socket 8 and the claws 35 have latched into the grooves 37.

FIG. 5 shows an electronic fuse 28 with ignition line 31 coupledthereto. As a result of inserting the plug 30 into the plug socket 8, aplug connection 38 will have been established. It can be seen from thesectional drawing that the sealing ferrule 33 has been completelyinserted into the plug socket 8 and the claws 35 of the stop lamellae 34have engaged into the grooves 37 of the plug socket 8. As a result,unintentional separation of the plug connection is precluded. The plug30 can only be pulled out of the plug socket 8 if the lamellae 34 arebent so far outwards that the claws 35 are no longer engaged with thegrooves 37.

The present exemplifying embodiment shows an electronic fuse, theterminal connection of which is formed as a plug socket. The subject ofthe invention is not changed if the coupling portions of the plugconnection are interchanged, chat is, if the head portion of theelectronic fuse in formed as the plug and the coupling portion of thefuse line is formed as the plug socket.

Furthermore, FIG. 5 shows a coding 39 on the periphery of the firsthousing case. Tis gives information, for example, on the associated timestage, the manufacturer and possibly which detonating capsules it issuitable for. The coding 40 on the second housing case 21, thedetonating capsule, facilitates the association with a suitable basefuse 17.

A further exemplifying embodiment of a plug connection is shown on anenlarged scale in FIGS. 6a to 6 c. Features that correspond with theprevious exemplifying embodiment are denoted by the same referencenumerals.

In FIG. 6a an electronic fuse 28 partly in section, there is shown, inwhich the first housing case 102 is formed as a plug socket 42. Thesection extends though the locking elements with which the plug 44 issecured in the plug socket 42 against being pulled out unintentionally.

In contrast to the previous exemplifying embodiment, the outer housingcase extends beyond the cylindrical body 10, in which the hybrid 1 withthe IC package 3 is embedded. The contact pins 7, to which the ignitionline 31 is connected by means of the plug 44, project from the end faceof the cylindrical body 10.

The ignition line 31 with the contact sleeves 32 connected thereto isembedded in the plug 44. As can be seen from FIG. 6c, the plug 44 hasso-called stop lamellae 45 on opposing sides, each of which lamellaegives way on account of an undercut 46 when the plug 44 is inserted intothe plug socket 42 in order then to latch with its spur 47 in a window48 in the wall of the housing case. The plug 44 is thereby securedagainst being unintentionally pulled out of the plug socket 42. Sincethe plug socket 42 encompasses the plug 44 as far as and beyond theregion of the contact sleeves 32, the plug connection 38 is secured in aparticularly advantageous manner against bending stresses and kinking,this being advantageous in particular when used, for example, inquarries, mines or in the case of explorations.

FIG. 6b shows a section through the orientation aids on the plug and theplug socket, with which aids just one single orientation of the couplingportions is possible in order to establish a plug connection. Theorientation aid on the plug socket 42 of the electronic fuse 28 is aV-shaped bead 49 in the wall of the first housing case 102. Associatedwith this bead 49 in the plug 44 as an orientation aid is a V-shapedgroove 50. This can be seen particularly clearly in FIG. 6c which showsa cross section through the plug connection 38 at the point specified inFIG. 6b. The plug and plug socket can only be plugged into each other ifthe bead 49 of the plug socket 42 is opposite the groove 50 of the plug44. Interchanging the terminals of the ignition line 31 is therebyprecluded.

FIG. 7 shows an exemplifying embodiment of a plug connection 38 with anencapsulated cinch plug Such a plug connection has the advantage that nomeasures need to be taken for position-orientated insertion of the pluginto the socket, this substantially simplifying the assembly. The hybrid1, which is embedded in a hardened, non-metallic material 9, isconnected, in the present exemplifying embodiment, by way of terminals 6to a plug socket 51. This plug socket 51 consists of two concentriccontacts 52 and 53 in the form of sheet-metal cylinders which projectout of the free end 43 of the first housing case 202.

The plug 54 on the ignition line 31 preferably consists of an elasticplastics material and contains the contact pin 55, which can be insertedinto the inner contact 53 of the plug socket 51, and the contact sleeve57, which is surrounded by a concentric gap 56, for contacting the outerterminal 52.

The contacts are additionally protected against moisture by a cap 58which is sipped over the housing case 202. In this connection, awedge-shaped bulging portion 59 engages into a bead 60 in the housingcase 202 and thus forms a form-locking means of securing and sealing theplug connection 38.

What is claimed is:
 1. Trigger unit for initiating pyrotechnic elements,comprising a switch and control unit, and ignition means and a chargebody, with the switch and control unit being ignited by means of anelectrical coupling by way of a line, characterized in that the switchand control unit is surrounded by a first housing case, in that thisfirst housing case is connected to a second housing case which containsthe charge body, and in that the ignition means goes right into thissecond housing case so as to be surrounded by the second housing casebut not the first housing case.
 2. Trigger unit according to claim 1,characterized in that the diameter of the first housing case,surrounding the switch and control unit is larger than the diameter ofthe second housing case containing the charge body.
 3. Trigger unitaccording to claim 1, characterized in that the first housing case has agreater wall thickness than the second housing case.
 4. Trigger unitaccording to claim 1, characterized in that the first housing caseconsists of a material which differs from the material of the secondhousing case.
 5. Trigger unit according to claim 1, characterized inthat the first housing case withstands a dynamic pressure load of atleast 100 MPa without deformation.
 6. Trigger unit according to claim 1,characterized in that the switch and control unit in the first housingcase is embedded in a hardened, non-metallic material.
 7. Trigger unitaccording to claim 1, characterized in that the material that surroundsthe switch and control unit projects out of the first housing case inthe form of a stopper at least on the side that faces the second housingcasing, and in that this stopper can be inserted into the second housingcase as a sealing and fastening element.
 8. Trigger unit according toclaim 1, characterized in that, at its end that is remote from thesecond housing case, the first housing case carries the coupling portionof a plug connection between the trigger unit and the line thatestablishes the electrical coupling.
 9. Trigger unit according to claim8, characterized in that the coupling portion is formed from thematerial which surrounds the switch and control unit.
 10. Trigger unitfor initiating pyrotechnic elements, comprising a switch and controlunit, an ignition means and a charge body, with the switch and controlunit being ignited by means of an electrical coupling by way of a line,characterized in that the switch and control unit is surrounded by afirst housing case is connected to a second housing case which containsthe charge body, in that the ignition means goes right into this secondhousing case, in that, at its end that is remote from the second housingcase, the first housing case carries the coupling portion of a plugconnection between the trigger unit and the line that establishes theelectrical coupling in that the free end of the first housing case isformed as a plug socket or contains a plug socket.
 11. Trigger unitaccording to claim 8, characterized in that the coupling portions of theplug connection are equipped with an orientation aid so that connectionof the two coupling portions is possible in just one orientation. 12.Trigger unit according to claim 8, characterized in that the couplingportions of the trigger unit and the line are equipped with interlockinglocking elements which establish a connection that is secured againstbeing undone unintentionally.
 13. Trigger unit according to claim 8,characterized in that at least one coupling portion of the plugconnection is equipped with a sealing element.
 14. Trigger unitaccording to claim 8, characterized in that the number of contacts ofthe plug and the number of contacts of the plug socket are matched tothe use of the trigger unit.
 15. Trigger unit according to claim 1,characterized in that integrated circuits are provided in an IC packagefor addressing and controlling the trigger unit.
 16. Trigger unitaccording to claim 1, characterized in that at least the first housingcase has an identifying marking from which data that is relevant to theuse of the trigger unit can be read off.
 17. Trigger unit according toclaim 16, characterized in that the second housing case likewise bearsan identifying marking, and in that it is possible to associate asuitable switch and control unit with a charge body with the aid of theidentifying marking of the first housing case and the identifyingmarking of the second housing case.